Final answer:
The NAACP effectively used the nation's judicial system to implement lasting change in America, notably through legal challenges leading to significant civil rights victories.
Step-by-step explanation:
Among the civil rights organizations that effectively used the nation's judicial system to implement lasting change in America, the National Association for the Advancement of Colored People (NAACP) stands out. Founded in 1909, the NAACP led the way in sponsoring a host of legal challenges against segregation.
The organization was pivotal in securing African American civil rights, frequently utilizing the judicial system for this purpose. Between 1938 and 1961, the NAACP took thirty-two cases to the US Supreme Court and won twenty-nine of them. Some of their most significant legal victories included cases that led to the desegregation of public education and advances in the rights of African Americans to equality in employment, voting, and other areas of public life.